Moessbauer studies on ferrimagnetic FeCr{sub 1.7}Al{sub 0.3}S{sub 4} Kim, Chin Mo; Kim, Chul Sung [Kookmin University, Seoul (Korea, Republic of)] 75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; CHALCOGENIDES; CRYSTAL STRUCTURE; FERRIMAGNETIC MATERIALS; IRON COMPLEXES; IRON IONS; MAGNETIZATION; MATERIALS TESTING; MOESSBAUER EFFECT; POLYCRYSTALS; TEMPERATURE DEPENDENCE; X-RAY DIFFRACTION Polycrystalline Al-doped FeCr{sub 1.7}Al{sub 0.3}S{sub 4} has been studied with X-ray diffraction, magnetization, and Moessbauer spectroscopy measurements. The crystal structure was found to be a cubic spinel with a space group of Fd-3m, and the lattice constant was 10.004 A. The magnetic susceptibility followed the Curie-Weiss law with a positive {theta}{sub cw} = 114 K, showing a ferrimagnetic behavior. The value of the magnetization at 5 K was found to be 1.12 {mu}{sub B}. Moessbauer spectra of FeCr{sub 1.7}Al{sub 0.3}S{sub 4} were obtained at various temperatures ranging from 4.2 to 300 K. Both the magnetic hyperfine field (H{sub hf}) and the polar angle ({theta}) reached their maximum values at 60 K and had similar temperature dependences. However, the azimuthal angle ({phi}) remained constant at temperatures below 60 K and started increasing with temperature at temperatures above 60 K. From the Moessbauer spectra of FeCr{sub 1.7}Al{sub 0.3}S{sub 4} at 4.2 K, we obtained the following Moessbauer parameters: H{sub hf} = 128 kOe, {Delta}E{sub Q} = 2.42 mm/s, {theta} = 20.0 .deg. , {phi} = 0.0 .deg. , {eta} = 0.8, and R = 2.8. The isomer shift of FeCr{sub 1.7}Al{sub 0.3}S{sub 4} at 4.2 K was 0.83 mm/s relative to the Fe metal, which is consistent with the Fe{sup 2+} valence state. Korea, Republic of 2010-03-15 English Journal Article Journal Name: Journal of the Korean Physical Society; Journal Volume: 56; Journal Issue: 3; Other Information: 18 refs, 5 figs, 2 tabs Medium: X; Size: page(s) 823-826 https://doi.org/ [] 3 56 Journal ID: ISSN 0374-4884; TRN: KR1301072036384 KRN 2013-05-13 22077209